Power lawn mowers typically incorporate one or more controls for operating various systems on the mower. Among these controls are the engine speed control, engine on/off control, engine choke control, mower propulsion control, and a blade brake clutch (BBC) control. This invention centers on the Propulsion and BBC controls.
Lawn mower propulsion controls are utilized on lawn mowers that are "self-propelled." "Self-propelled" mowers incorporate a power transmission system which transmits engine power to the mower wheels to propel the mower. The propulsion control is typically located on the handlebar assembly of the lawn mower for ease of operator access. The propulsion control allows the operator to start or stop the transmission of power from the engine to the wheels. Some propulsion controls also allow the operator to choose a propulsion speed by changing gear ratios within the power transmission system. Furthermore, the operator can usually change the propulsion speed of the mower by varying the engine speed control which is also typically mounted on the handlebar assembly.
BBC controls are also typically mounted on the mower handlebar assembly. Blade brake clutches control the transmission of power between the mower engine and the cutting blade. The blade brake clutch typically operates in one of two modes. In the first mode, the engine does not transmit power to the mower blade, and the blade is braked so as to prevent rotation. In the second mode, the brake is released from the mower blade and the engine and blade are operatively coupled so that power is transmitted from the engine to the mower blade. Typically, a control is mounted on the handlebar of the mower so that the operator can select one of the two modes of operation of the BBC. The BBC handlebar control mechanism is typically configured so that the BBC cannot be put into the second mode by an inadvertent movement on the operator's part. Safety concerns mandate that the BBC control requires an intentional, multi-direction movement of the control by the operator to put the BBC into the second mode of operation. Without this requirement, inadvertent contact of the BBC control by the operator could result in engagement of the mower blade.
Blade brake clutches and their controls also typically incorporate means biasing the BBC to the first mode of operation wherein the blade is braked and the engine is disconnected from the blade.
One prior art BBC control incorporates an integral propulsion control. In this control, the operator can choose to propel the mower by lifting the combination control bail upward. By doing so, the propulsion system is engaged but the BBC stays in the first mode of operation wherein the blade is braked and the engine is operatively disconnected from the blade. If the operator releases the control bail, the propulsion of the mower stops and the control returns to its neutral position. If the operator then wants to put the BBC into the second mode of operation, the operator must push down on the bail and then pull the bail up to the same position the bail was at in the propulsion mode. This two step movement of the bail by the operator results in the BBC transmitting power from the engine to the now un-braked blade, and the transmission of power from the engine to the mower wheels for more propulsion. If the operator now releases the control bail, the control bail returns to neutral, the mower propulsion stops, and the BBC returns to its first mode of operation wherein the blade is braked and the engine is operatively disconnected from the mower blade.
Another prior art control system provides separate control bails for propulsion and BBC operation. This system provides one control bail for propulsion. The operator must lift the propulsion control bail to engage the mower propulsion system, which then transmits power from the engine to the mower wheels, propelling the mower. If the operator releases the propulsion control bail, the propulsion system is disengaged and the propulsion of the mower is stopped. The propulsion control bail also returns to its neutral position. If the operator then wants to put the BBC into the second mode of operation, the operator must push a BBC finger control interlock switch forward, and then pull the BBC bail control back. The movement of the two BBC controls by the operator results in the BBC transmitting power from the engine to the now un-braked blade, causing the blade to rotate. The operator may still also control the propulsion of the mower by moving the propulsion control bail in the manner described above. If the operator releases the BBC control bail, the control bail returns to neutral and the BBC returns to the first mode of operation wherein the blade is braked and the engine is operatively disconnected from the mower blade.
The present invention offers an alternate method of engaging the mower propulsion system and BBC. In particular, a preferred propulsion and BBC control system according to the present invention accommodates ease of operation in that it incorporates a control arm operatively coupled to a BBC and a mower propelling means and also incorporates pivot means operatively connecting the control arm to the lawn mower wherein the pivot means establishes a pivot axis and wherein the propelling means is engaged when the control arm is generally rotated about the pivot axis and wherein the BBC and the propelling means are engaged when the control arm is generally displaced axially along the pivot axis and then generally rotated about the pivot axis.